Faculty Spotlight

David Glanzman

We are interested in the cell biology of learning and memory in simple
organisms. We use two animals in our research, the marine snail Aplysia
californica, and the zebrafish (Danio rerio).
Work on Aplysia: This invertebrate has a comparatively simple nervous
system (~ 20,000 neurons) that provides a valuable model system for
neurobiological investigations of simple forms of learning, including
habituation, sensitization, and classical conditioning. Another
advantage of Aplysia is that neurons known to mediate specific behaviors
in the animal can be placed into dissociated cell culture where they
will reform their synaptic connections. These in vitro synapses are
extremely useful for cellular and molecular analyses of long-term
memory. Currently, my laboratory is attempting to understand how
long-term memories persist. We have found that an isoform of protein
kinase C, known as PKM, appears to play a key role in the maintenance of
long-term sensitization in Aplysia.
Work on the zebrafish: The zebrafish is a popular organism for molecular
and genetic studies of development. However, it has significant
advantages for cell biological analyses of behavior, including learning
and memory. The zebrafish is amenable to both forwards and reverse
genetics. Furthermore, although it is a vertebrate with a complex
vertebrate nervous system, it possesses reflexive behaviors that are
mediated by relatively simple neural circuits in the spinal cord and
brainstem. Finally, zebrafish larvae are transparent, which facilitates
the use of imaging techniques to study learning-related neural activity
in the intact animal. We are interested in the neural basis of
nonassociative and associative modification of the zebrafish’s startle
reflex. At present we are using electrophysiological, genetic, and
imaging techniques to analyze the mechanisms of habituation and
sensitization of the startle reflex. In the future we hope to examine
classical conditioning of this reflex.